Jennings Electronic Industries (JEI) - Phaser

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
Post Reply
User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

Yesterday this pedal came in the mail. I was fascinated by the origin (from the hands of the AC30 designers) but also wanted to hear it in action.

Fired up the unit has a HUGE volume boost with the phaser engaged or in bypass mode. It is not true bypass I suppose. The phaser has no LFO and can be used by rocking the pedal forwards and backwards. It can be activated the same way as a crybaby wah.

The sound is surprisingly nice. A very complex phaser sound that I was not expecting from it. Looking at the circuit it only has transistors, no IC can be found. (if I recall, I've never seen a pure transistor based phaser).

More pics will follow; I'll trace it when I got some spare time!
$_57.JPG
http://www.hendrixguitars.com/Ef230.htm

http://www.effectsdatabase.com/model/je
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
Fender3D
Cap Cooler
Information
Posts: 573
Joined: 08 Aug 2009, 02:40
Location: Helltaly
Has thanked: 121 times
Been thanked: 153 times

Post by Fender3D »

The very first issue of Elektor in Italy, back in the late '70-early '80, featured a phaser circuit, it had two 1-transistor-phase stages (outputs on E and C) ala ***vibe, a dual gang pot instead of LDRs, I'm sorry but I don't recall what the input and input stages were...

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

Oops, forgot the univibe :)

That one is a pure transistor phaser
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

DSCF6084.jpg
DSCF6093.jpg
DSCF6097.jpg
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

DSCF6098.jpg
DSCF6099.jpg
DSCF6100.jpg
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

And the schematic!!
JEI - Phaser.JPG
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
tube-exorcist
Resistor Ronker
Information
Posts: 445
Joined: 05 Jul 2007, 20:09
Has thanked: 173 times
Been thanked: 67 times

Post by tube-exorcist »

The original circuit can be found in Practical Electronics October 1973. The potentiometer should be alogarithmic type.
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

tube-exorcist wrote:The original circuit can be found in Practical Electronics October 1973. The potentiometer should be alogarithmic type.
Nice! I can't find that issue online; would you have one? I'm interested in the article....
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
tube-exorcist
Resistor Ronker
Information
Posts: 445
Joined: 05 Jul 2007, 20:09
Has thanked: 173 times
Been thanked: 67 times

Post by tube-exorcist »

Bernardduur wrote:
tube-exorcist wrote:The original circuit can be found in Practical Electronics October 1973. The potentiometer should be alogarithmic type.
Nice! I can't find that issue online; would you have one? I'm interested in the article....
Sorry, but I don´t have an original one - I found the article on Mar 24, 2001.... ONLINE. And yes, it is still there waiting for interested ones:

http://www.synthdiy.com/show/?id=1118

(Download link at the the right bottom "pha.pdf".)
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."

User avatar
Manfred
Tube Twister
Information
Posts: 1936
Joined: 04 Apr 2009, 23:42
Has thanked: 1668 times
Been thanked: 1344 times

Post by Manfred »

Hi Bernardduur,

thanks for dissectioning, great!
How is the size of the PCB?
Do you made a shot of the component side of the PCB too,
there are some components hidden by the plug sockets on the device shot?
I intend to create a replica PCB.

User avatar
Fender3D
Cap Cooler
Information
Posts: 573
Joined: 08 Aug 2009, 02:40
Location: Helltaly
Has thanked: 121 times
Been thanked: 153 times

Post by Fender3D »

lol
:mrgreen:

looking at the several magazines publishing(ed) this...
it may be a good argument for the "The Big Catfight: ethics/cloning/copying/stealing/personal" thread... :horsey:

User avatar
Manfred
Tube Twister
Information
Posts: 1936
Joined: 04 Apr 2009, 23:42
Has thanked: 1668 times
Been thanked: 1344 times

Post by Manfred »

Fender3D wrote:lol
:mrgreen:

looking at the several magazines publishing(ed) this...
it may be a good argument for the "The Big Catfight: ethics/cloning/copying/stealing/personal" thread... :horsey:
I guess there is no argument, because it is a discontinued product since more than 40 years. 8)
Of course for noncommercial use only. :wink:

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1217
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

@ tube exorcist: Thanks for the link!!

@ Manfred: here ya go
DSCF6099.jpg
Size: 7cm x 5.5cm
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
Manfred
Tube Twister
Information
Posts: 1936
Joined: 04 Apr 2009, 23:42
Has thanked: 1668 times
Been thanked: 1344 times

Post by Manfred »

Hi Bernardduur,

thanks for the shot and the board size.

User avatar
Manfred
Tube Twister
Information
Posts: 1936
Joined: 04 Apr 2009, 23:42
Has thanked: 1668 times
Been thanked: 1344 times

Post by Manfred »

I create the PCB layout clone according to the the shots.
JEI3Layout.JPG
JEI3_PCB.jpg

Post Reply